Freezing influences diffusion of reducing sugars in carrot cortex

The loss of reducing sugars from raw and previously frozen carrot cortex tissue immersed in warm water was studied as a function of temperature (40–100°C). Leaching was described as a diffusional mechanism by application of Fick's 2nd law. This approach successfully modeled losses from raw carrots at temperatures higher than 60°C. At low temperatures diffusion was much slower, due to a high resistence of the tissues to mass transfer, and Fick's 2nd law could not be applied. Previously frozen carrots showed a Fickian behaviour through the range of temperatures and diffusivities were much higher. Dependence of diffusivity on temperature followed an Arrhenius type equation for the two cases. However, the activation energy of pre-frozen carrots was lower, indicating loss of sensitivity to temperature variations.